The Color of the Elements: A Combined Experimental and Theoretical Electron Density Study of ScB2C2

The chemical or physical control parameters for the onset of superconductivity in MB2C2 hetero‐graphene materials are unclear. This is mainly due to the almost ubiquitous positional B/C disorder, rendering the description of real structures of borocarbides into one of the most challenging problems in materials science. We will show that high‐resolution X‐ray diffraction data provides all the essential information to decode even complex coloring problems due to B/C disorder. Electron density studies and subsequent analyses of the fine structure of the Laplacian of the electron density resolves the local electronic structure of ScB2C2 at sub‐atomic resolution and allows for an unequivocal identification of all atoms involved in the coloring scenario. This information could finally be used to identify the electron deficient character of the B/C layers in ScB2C2 and to synthesize the first bimetallic hetero‐metallocene with lithium and scandium atoms embedded in the pentagonal and heptagonal voids, respectively. Electron deficiency: The high‐resolution X‐ray diffraction provides all the essential information to decode even complex coloring problems in chemistry such as the disorder‐induced electronic doping in ScB2C2. This information lead to the synthesis of the first bimetallic hetero‐metallocene with lithium and scandium atoms embedded in pentagonal and heptagonal voids, respectively.